| 摘要 |
<p>A stabilised high vacuum drying installation for industrial hides and similar products includes a plurality of drying beds (2, 2', 2'') with heating platforms (3, 3', 3'') and hermetic covers (4, 4', 4''), vacuum means (7) connected to the drying beds to extract vapours coming from the hides and to reduce the pressure to minimum working values (Pi), a circuit with valve means (10, 10', 10''; 11, 11', 11'') to selectively connect the drying beds to the vacuum means. The valve means include, downstream of every drying bed, at least one cutoff valve (10, 10', 10'') for selectively connecting such bed, initially at atmospheric pressure, to the vacuum means (7), and at least one check valve (11, 11', 11'') for isolating automatically the remaining beds already at working pressure so as to avoid pressure oscillations in their interior. The vacuum means (7) include a primary vacuum pump (8) suitable to reduce the pressure in the circuit to a predetermined value (Ps) superior to the working minimum value (Pi) and a secondary vacuum pump (9) suitable to co-operate with the primary vacuum pump (8) to reduce the pressure in the circuit to the minimum working value (Pi).</p> |
